<template>
  <div class="type-nav">
    <div class="container">
      <div @mouseleave="leaveShow" @mouseenter="enterShow">
        <h2 class="all">全部商品分类</h2>
        <!-- 过渡动画 -->
        <transition name="sort">
          <div class="sort" v-show="show">
            <div class="all-sort-list2" @click="goSearch">
              <div
                class="item"
                v-for="(c1, index) in categoryList"
                :key="c1.categoryId"
              >
                <h3
                  :class="{ cur: currentIndex == index }"
                  @mouseenter="changeIndex(index)"
                >
                  <a
                    :data-categoryName="c1.categoryName"
                    :data-category1Id="c1.categoryId"
                    >{{ c1.categoryName }}</a
                  >
                </h3>
                <div
                  class="item-list clearfix"
                  :style="{ display: currentIndex == index ? 'block' : 'none' }"
                >
                  <div class="subitem">
                    <dl
                      class="fore"
                      v-for="c2 in c1.categoryChild"
                      :key="c2.categoryId"
                    >
                      <dt>
                        <a
                          :data-categoryName="c2.categoryName"
                          :data-category2Id="c2.categoryId"
                          >{{ c2.categoryName }}</a
                        >
                      </dt>
                      <dd>
                        <em v-for="c3 in c2.categoryChild" :key="c3.categoryId">
                          <a
                            :data-categoryName="c3.categoryName"
                            :data-category3Id="c3.categoryId"
                            >{{ c3.categoryName }}</a
                          >
                        </em>
                      </dd>
                    </dl>
                  </div>
                </div>
              </div>
            </div>
          </div>
        </transition>
      </div>
      <nav class="nav">
        <a href="###">服装城</a>
        <a href="###">美妆馆</a>
        <a href="###">尚品汇超市</a>
        <a href="###">全球购</a>
        <a href="###">闪购</a>
        <a href="###">团购</a>
        <a href="###">有趣</a>
        <a href="###">秒杀</a>
      </nav>
    </div>
  </div>
</template>
      
<script>
import { mapState } from 'vuex' //引入vuex仓库
import throttle from 'lodash/throttle' //按需引入lodash节流
export default {
  name: 'TypeNav',
  data() {
    return {
      currentIndex: -1, //决定了到底那个h3身上有类名
      show: true, //控制商品列表的显示
    }
  },
  //在mounted生命周期函数中发送请求
  mounted() {
    if (this.$route.path != '/home') {
      //如果不是home路由使show=false
      this.show = false
    }
  },
  computed: {
    //从仓库中取state
    ...mapState({
      categoryList: (state) => state.home.categoryList,
    }),
  },
  methods: {
    //使用lodash节流
    changeIndex: throttle(function (index) {
      //用于修改组件实例身上的currentIndex的属性值
      this.currentIndex = index
    }, 50),
    //跳转Search路由
    goSearch(event) {
      //event.target获取到的是出发事件的元素
      let node = event.target
      //给a标签添加了自定义属性
      let { categoryname, category1id, category2id, category3id } = node.dataset
      //if一定是a标签
      if (categoryname) {
        //准备路由跳转的参数对象
        let location = { name: 'search' }
        let query = { categoryName: categoryname }
        //一级目录
        if (category1id) {
          query.category1Id = category1id
          //二级目录
        } else if (category2id) {
          query.category2Id = category2id
          //三级目录
        } else {
          query.category3Id = category3id
        }
        //如果路由跳转的时候，带有params参数,则一同携带传递
        if (this.$route.params) {
          location.params = this.$route.params
          //动态给location配置对象添加query属性
          location.query = query
          //路由跳转
          this.$router.push(location)
        }
      }
    },
    //鼠标进入列表展示动画
    enterShow() {
      if (this.$route.path != '/home') {
        this.show = true
      }
    },
    //当鼠标离开的时候，让商品分类列表进行隐藏
    leaveShow() {
      this.currentIndex = -1
      //在search路由下才会控制show
      if (this.$route.path != '/home') {
        this.show = false
      }
    },
  },
}
</script>
      
<style lang="less" scope>
.type-nav {
  border-bottom: 2px solid #e1251b;
  .container {
    width: 1200px;
    margin: 0 auto;
    display: flex;
    position: relative;

    .all {
      width: 210px;
      height: 45px;
      background-color: #e1251b;
      line-height: 45px;
      text-align: center;
      color: #fff;
      font-size: 14px;
      font-weight: bold;
    }

    .nav {
      a {
        height: 45px;
        margin: 0 22px;
        line-height: 45px;
        font-size: 16px;
        color: #333;
        &:hover {
          color: #e1251b;
        }
      }
    }

    .sort {
      position: absolute;
      left: 0;
      top: 45px;
      width: 210px;
      height: 461px;
      position: absolute;
      background: #fafafa;
      z-index: 999;

      .all-sort-list2 {
        .item {
          h3 {
            line-height: 28px;
            font-size: 14px;
            font-weight: 400;
            overflow: hidden;
            padding: 0 20px;
            margin: 0;

            a {
              color: #333;
              font-size: 15px;
              cursor: pointer;
              &:hover {
                color: rgb(200, 22, 35);
              }
            }
          }

          .item-list {
            display: none;
            position: absolute;
            width: 734px;
            min-height: 460px;
            background: #f7f7f7;
            left: 210px;
            border: 1px solid #ddd;
            top: 0;
            z-index: 9999 !important;

            .subitem {
              float: left;
              width: 650px;
              padding: 0 4px 0 8px;

              dl {
                border-top: 1px solid #eee;
                padding: 6px 0;
                overflow: hidden;
                zoom: 1;

                &.fore {
                  border-top: 0;
                }

                dt {
                  float: left;
                  width: 60px;
                  line-height: 22px;
                  text-align: right;
                  padding: 3px 6px 0 0;
                  font-weight: 700;
                  a {
                    font-size: 14px;
                    color: #000;
                    cursor: pointer;
                    &:hover {
                      color: rgb(200, 22, 35);
                    }
                  }
                }

                dd {
                  float: left;
                  width: 415px;
                  padding: 3px 0 0;
                  overflow: hidden;

                  em {
                    float: left;
                    height: 14px;
                    line-height: 14px;
                    padding: 0 8px;
                    margin-top: 5px;
                    border-left: 1px solid #ccc;
                    a {
                      cursor: pointer;
                      font-size: 12px;
                      &:hover {
                        color: rgb(200, 22, 35);
                      }
                    }
                  }
                }
              }
            }
          }
        }
        .cur {
          background: rgb(217, 217, 217);
        }
      }
    }
    .sort-enter,
    .sort-leave-to {
      //进入开始,离开结束
      height: 0;
      opacity: 0;
    }
    .sort-enter-to,
    .srot-leave {
      //进入结束后，离开开始
      height: 461px;
      opacity: 1;
    }
    .sort-enter-active,
    .sort-leave-active {
      //进入,离开动画
      transition: all 0.2s linear;
    }
  }
}
</style>